1. Field of the Invention
The present invention relates to a communication system, an image processing apparatus, an image processing method, an authentication server, an image managing method, an image managing program, and an image processing system. In particular, the invention relates to a communication system, an image processing apparatus, an image processing method, an authentication server, an image managing method, an image managing program, and an image processing system that carry out predetermined image processing on a protected image that has been subjected to a predetermined protection process.
2. Description of the Related Art
Due to the development of application software that handles image data of digital images including digital photographs and advances in printing technology, the resolution of image data of digital images has become higher and the scale of the market for businesses based on digital images has been expanding year by year. Together with this, the volume of image data distributed onto the market has been increasing and the number of digital images available on the market has been increasing steadily.
For businesses based on digital images, a host, which includes a content management server for managing digital images, provides a client with an image processing system that offers users fee-based delivery services of image data. Using the image processing system, the client can release sample images produced by subjecting image data to a predetermined process to users. Each user can pay a predetermined fee to the client via the content management server. After password authentication, the user can download and thereby obtain the desired image data from the content management server. Note that a typical print authentication technology has been disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2004-094920.
However, once obtained after the password authentication, the image data can freely and easily be image-processed, for example, copied by the user. This makes it difficult for the client to protect the copyright of the distributed image data, resulting in lowered security of the image data.
Also, in the image processing system, the increased volume and number of image data makes the processing required for the content management server to perform to manage high-resolution image data increasingly complex, which increases the load upon the content management server for handling image data. In addition, the management of accounting information for respective image data and password authentication before downloading create a further load, and therefore, there is a demand to reduce such load to improve the performance of the image processing system.